Impact of structural uncertainties on the buckling strength of cylindrical GLARE panels subjected to uniform compression

Costas Kalfountzos,George Bikakis,Efstathios Theotokoglou,S Pantelakis,K Tserpes,G Lampeas

doi:10.1051/matecconf/202134901003

Costas Kalfountzos, George Bikakis + Show 4 more

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https://doi.org/10.1051/matecconf/202134901003

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Abstract

The objective of this article is the investigation of the elastic buckling strength of cylindrical simply supported GLARE (GLAss REinforced) panels subjected to axial compression using probabilistic analysis methods, so that the effect of uncertainties associated with material properties and dimensions of the panels on their elastic buckling load can be evaluated. The mechanical properties of aluminum along with the dimensions of aluminum and unidirectional (UD) glass-epoxy layers are considered to be random input variables whereas the critical buckling load is defined as a random output parameter. The employed eigenvalue buckling analysis and the probabilistic finite element analysis were carried out with ANSYS software. The Probabilistic Design System (PDS), along with the Monte Carlo Simulation and the Latin Hypercube Sampling method were used for the calculations. It is found that the thickness of aluminum layers has the strongest effect on the buckling strength, among the considered random input variables. It is also demonstrated that there is a considerable probability for the buckling load of GLARE panels to be overestimated when a deterministic analysis is conducted.

Highlights

Fiber Metal Laminates (FMLs) are hybrid composite materials, which were originally developed for application in primary aircraft structures
It is noted that the findings described in this paragraph are valid for the Nzc histograms of all GLARE 5 and GLARE 3 panels of our probabilistic analysis, regardless of their bc
Using the Probabilistic Design System (PDS) and the aforementioned uncertainties, which are realistic for practical applications, we found that there is a considerable probability to overestimate the critical buckling load of the panels if these uncertainties are ignored

Summary

Introduction

Fiber Metal Laminates (FMLs) are hybrid composite materials, which were originally developed for application in primary aircraft structures. FMLs combine significant advantages of metals and fiber-reinforced composites. They demonstrate high fatigue resistance, high fracture toughness and excellent impact resistance which is comparable with the impact resistance of their constituent aluminum alloys. Excellent moisture, corrosion and fire resistance are some other significant advantages of FMLs, which make them ideal for aerospace applications [1]. GLARE (GLAss REinforced) is the most successful FML up to now, since it has been applied in the production of primary aircraft structures, such as the fuselage of the Airbus A380 [2]. The unstiffened cylindrical panels are employed in a large number of structures subjected to high compressive loads which are prone to buckling. The calculation of elastic buckling load of the unstiffened panels is necessary for the consideration of the local buckling modes in the analysis of the, more widely used, stringer-

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